Add of_regulator_get_optional() and Fix MTK Power

Merge series from Chen-Yu Tsai <wenst@chromium.org>:

At ELCE, Sebastian told me about his recent work on adding regulator
supply support to the Rockchip power domain driver [2], how the MediaTek
driver has been using the existing devm_regulator_get() API and
reassigning different device nodes to the device doing the lookup, and
how the new of_regulator_get_optional() is the proper fit for this.

Patch 1 adds a new of_regulator_get_optional() function to look up
regulator supplies using device tree nodes.

Patch 2 adds a devres version of the aforementioned function at
Sebastian's request for the two power domain drivers.

4 files changed, 98 insertions, 14 deletions

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 1179766811f5..d0b3879f2746 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1959,8 +1959,8 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
 	regulator_supply_alias(&dev, &supply);
 
 	/* first do a dt based lookup */
-	if (dev && dev->of_node) {
-		r = of_regulator_dev_lookup(dev, supply);
+	if (dev_of_node(dev)) {
+		r = of_regulator_dev_lookup(dev, dev_of_node(dev), supply);
 		if (!IS_ERR(r))
 			return r;
 		if (PTR_ERR(r) == -EPROBE_DEFER)
diff --git a/drivers/regulator/devres.c b/drivers/regulator/devres.c
index 1b893cdd1aad..36164aec30e8 100644
--- a/drivers/regulator/devres.c
+++ b/drivers/regulator/devres.c
@@ -749,3 +749,42 @@ void *devm_regulator_irq_helper(struct device *dev,
 	return ptr;
 }
 EXPORT_SYMBOL_GPL(devm_regulator_irq_helper);
+
+#if IS_ENABLED(CONFIG_OF)
+static struct regulator *_devm_of_regulator_get(struct device *dev, struct device_node *node,
+						const char *id, int get_type)
+{
+	struct regulator **ptr, *regulator;
+
+	ptr = devres_alloc(devm_regulator_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	regulator = _of_regulator_get(dev, node, id, get_type);
+	if (!IS_ERR(regulator)) {
+		*ptr = regulator;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return regulator;
+}
+
+/**
+ * devm_of_regulator_get_optional - Resource managed of_regulator_get_optional()
+ * @dev: device used for dev_printk() messages and resource lifetime management
+ * @node: device node for regulator "consumer"
+ * @id:  supply name or regulator ID.
+ *
+ * Managed regulator_get_optional(). Regulators returned from this
+ * function are automatically regulator_put() on driver detach. See
+ * of_regulator_get_optional() for more information.
+ */
+struct regulator *devm_of_regulator_get_optional(struct device *dev, struct device_node *node,
+						 const char *id)
+{
+	return _devm_of_regulator_get(dev, node, id, OPTIONAL_GET);
+}
+EXPORT_SYMBOL_GPL(devm_of_regulator_get_optional);
+#endif
diff --git a/drivers/regulator/internal.h b/drivers/regulator/internal.h
index 5b43f802468d..b3d48dc38bc4 100644
--- a/drivers/regulator/internal.h
+++ b/drivers/regulator/internal.h
@@ -65,14 +65,25 @@ static inline struct regulator_dev *dev_to_rdev(struct device *dev)
 	return container_of(dev, struct regulator_dev, dev);
 }
 
+enum regulator_get_type {
+	NORMAL_GET,
+	EXCLUSIVE_GET,
+	OPTIONAL_GET,
+	MAX_GET_TYPE
+};
+
 #ifdef CONFIG_OF
 struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
+					      struct device_node *np,
 					      const char *supply);
 struct regulator_init_data *regulator_of_get_init_data(struct device *dev,
 			         const struct regulator_desc *desc,
 				 struct regulator_config *config,
 				 struct device_node **node);
 
+struct regulator *_of_regulator_get(struct device *dev, struct device_node *node,
+				    const char *id, enum regulator_get_type get_type);
+
 struct regulator_dev *of_parse_coupled_regulator(struct regulator_dev *rdev,
 						 int index);
 
@@ -82,6 +93,7 @@ bool of_check_coupling_data(struct regulator_dev *rdev);
 
 #else
 static inline struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
+							    struct device_node *np,
 							    const char *supply)
 {
 	return ERR_PTR(-ENODEV);
@@ -114,12 +126,6 @@ static inline bool of_check_coupling_data(struct regulator_dev *rdev)
 }
 
 #endif
-enum regulator_get_type {
-	NORMAL_GET,
-	EXCLUSIVE_GET,
-	OPTIONAL_GET,
-	MAX_GET_TYPE
-};
 
 int _regulator_get_common_check(struct device *dev, const char *id,
 				enum regulator_get_type get_type);
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 3f490d81abc2..3d85762beda6 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -588,7 +588,8 @@ err_node_put:
 
 /**
  * of_get_regulator - get a regulator device node based on supply name
- * @dev: Device pointer for the consumer (of regulator) device
+ * @dev: Device pointer for dev_printk() messages
+ * @node: Device node pointer for supply property lookup
  * @supply: regulator supply name
  *
  * Extract the regulator device node corresponding to the supply name.
@@ -596,15 +597,16 @@ err_node_put:
  * Return: Pointer to the &struct device_node corresponding to the regulator
  *	   if found, or %NULL if not found.
  */
-static struct device_node *of_get_regulator(struct device *dev, const char *supply)
+static struct device_node *of_get_regulator(struct device *dev, struct device_node *node,
+					    const char *supply)
 {
 	struct device_node *regnode = NULL;
 	char prop_name[64]; /* 64 is max size of property name */
 
-	dev_dbg(dev, "Looking up %s-supply from device tree\n", supply);
+	dev_dbg(dev, "Looking up %s-supply from device node %pOF\n", supply, node);
 
 	snprintf(prop_name, 64, "%s-supply", supply);
-	regnode = of_parse_phandle(dev->of_node, prop_name, 0);
+	regnode = of_parse_phandle(node, prop_name, 0);
 	if (regnode)
 		return regnode;
 
@@ -628,6 +630,7 @@ static struct regulator_dev *of_find_regulator_by_node(struct device_node *np)
 /**
  * of_regulator_dev_lookup - lookup a regulator device with device tree only
  * @dev: Device pointer for regulator supply lookup.
+ * @np: Device node pointer for regulator supply lookup.
  * @supply: Supply name or regulator ID.
  *
  * Return: Pointer to the &struct regulator_dev on success, or ERR_PTR()
@@ -642,13 +645,13 @@ static struct regulator_dev *of_find_regulator_by_node(struct device_node *np)
  * * -%ENODEV if lookup fails permanently.
  * * -%EPROBE_DEFER if lookup could succeed in the future.
  */
-struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
+struct regulator_dev *of_regulator_dev_lookup(struct device *dev, struct device_node *np,
 					      const char *supply)
 {
 	struct regulator_dev *r;
 	struct device_node *node;
 
-	node = of_get_regulator(dev, supply);
+	node = of_get_regulator(dev, np, supply);
 	if (node) {
 		r = of_find_regulator_by_node(node);
 		of_node_put(node);
@@ -665,6 +668,42 @@ struct regulator_dev *of_regulator_dev_lookup(struct device *dev,
 	return ERR_PTR(-ENODEV);
 }
 
+struct regulator *_of_regulator_get(struct device *dev, struct device_node *node,
+				    const char *id, enum regulator_get_type get_type)
+{
+	struct regulator_dev *r;
+	int ret;
+
+	ret = _regulator_get_common_check(dev, id, get_type);
+	if (ret)
+		return ERR_PTR(ret);
+
+	r = of_regulator_dev_lookup(dev, node, id);
+	return _regulator_get_common(r, dev, id, get_type);
+}
+
+/**
+ * of_regulator_get_optional - get optional regulator via device tree lookup
+ * @dev: device used for dev_printk() messages
+ * @node: device node for regulator "consumer"
+ * @id: Supply name
+ *
+ * Return: pointer to struct regulator corresponding to the regulator producer,
+ *	   or PTR_ERR() encoded error number.
+ *
+ * This is intended for use by consumers that want to get a regulator
+ * supply directly from a device node, and can and want to deal with
+ * absence of such supplies. This will _not_ consider supply aliases.
+ * See regulator_dev_lookup().
+ */
+struct regulator *of_regulator_get_optional(struct device *dev,
+					    struct device_node *node,
+					    const char *id)
+{
+	return _of_regulator_get(dev, node, id, OPTIONAL_GET);
+}
+EXPORT_SYMBOL_GPL(of_regulator_get_optional);
+
 /*
  * Returns number of regulators coupled with rdev.
  */